POLYURETHANE
MACHINERY
CORPORATION
PH-2 SERVICE MANUAL
12. TROUBLESHOOTING
12.3 METERING PUMP-LINE
Figure 10: Metering Pump-Line (PL-9)
Frequent Pump-Line Problems
Metering pumps do not change direction and the pressures on both of
chemical gauges are lower than normal.
Page 38
Cavitation. Page 41
Pressure Loss: Discharge/Inlet Ball. Page 41
Follow the recommended procedure in the indicated order to solve the problem and avoid
unnecessary repairs. Make sure all Switches are in the correct position and Indicator Lights
ON before determining the existence of a fault.
• Problem: Metering pumps do not change direction and the pressures on both of
chemical gauges are lower than normal.
Solutions:
1. The Metering Pump Line has Reversing Plates which actuates two Proximity
Switches (EL-153), one at each end of the stroke. The Prox Switches in turn
actuate the appropriate Directional Valve Solenoid (HI-05003). Failure to make
contact with either Prox Switch may be caused by:
a. Deformation of the Reversing Plate.
b. Foreign material preventing the Reversing Plate from contacting the Prox
Switches.
2. Passing of the Reversing Plate beyond the Prox Switch may be caused by:
a. Failure of the Prox Switch and related components on the side of the over-run.
b. Failure of a component of the Directional Valve.
c. Mounting Plate (PU-07006) and/or Prox Switch is out of adjustment.
REVISION 1.2 38
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